[Darkness]

Maximum Torque, weight of bike and rider, and number of teeth on the front sprocket all affect maximum chain tension in service.

A 520 chain and sprockets combo MAY be OK for strength, but is not likely to last so long as a 525 setup. The problem comes if you don’t clean, lubricate and re-tension it regularly, making it more prone to wear.

It also makes it more prone to snapping, with associated risk of punching a hole in the crankcase!
A 520 is standard fitment on some of the 750s, but not the 750R.

I wouldn’t chance one on an 1100 unless racing and checking/replacing the chain for each meeting.